Run input transform final() when there is no input source

Synchronous input transforms were skipped when no `input`, `inputFile` or `stdin` source was provided, which meant their `final()` did not run and their errors were not reported.

Author: sindresorhus

lib/io/input-sync.js

@@ -17,7 +17,8 @@ const getInputFdNumbers = fileDescriptors => new Set(Object.entries(fileDescript
 const addInputOptionSync = (fileDescriptors, fdNumber, options) => {
 	const {stdioItems} = fileDescriptors[fdNumber];
 	const allStdioItems = stdioItems.filter(({contents}) => contents !== undefined);
-	if (allStdioItems.length === 0) {
+	// Even without an input source, generators must run so that `final` can produce input or report errors.
+	if (allStdioItems.length === 0 && stdioItems.every(({type}) => type !== 'generator')) {
 		return;
 	}
 

test/transform/generator-final.js

@@ -2,7 +2,12 @@ import assert from 'node:assert/strict';
 import test from 'node:test';
 import {execa, execaSync} from '../../index.js';
 import {foobarString} from '../helpers/input.js';
-import {getOutputAsyncGenerator, getOutputGenerator, convertTransformToFinal} from '../helpers/generator.js';
+import {
+	getOutputAsyncGenerator,
+	getOutputGenerator,
+	convertTransformToFinal,
+	throwingGenerator,
+} from '../helpers/generator.js';
 import {setFixtureDirectory} from '../helpers/fixtures-directory.js';
 
 setFixtureDirectory();
@@ -34,3 +39,99 @@ const testFinalNoOutput = async (final, execaMethod) => {
 test('Generators "final" can be used without "transform" nor output', () => testFinalNoOutput(getOutputGenerator, execa));
 test('Generators "final" can be used without "transform" nor output, sync', () => testFinalNoOutput(getOutputGenerator, execaSync));
 test('Generators "final" can be used without "transform" nor output, async', () => testFinalNoOutput(getOutputAsyncGenerator, execa));
+
+const testInputFinalEmpty = options => {
+	let finalCount = 0;
+	const chunks = [];
+	const {stdout} = execaSync('stdin.js', {
+		...options,
+		stdin: {
+			* transform(chunk) {
+				chunks.push(chunk);
+				yield chunk;
+			},
+			* final() {
+				finalCount += 1;
+				yield foobarString;
+			},
+			binary: true,
+		},
+	});
+	assert.equal(stdout, foobarString);
+	assert.equal(finalCount, 1);
+	assert.deepEqual(chunks, []);
+};
+
+test('Input generators "final" runs without an input source, sync', () => testInputFinalEmpty({}));
+test('Input generators "final" runs with an empty string input source, sync', () => testInputFinalEmpty({input: ''}));
+test('Input generators "final" runs with an empty Uint8Array input source, sync', () => testInputFinalEmpty({input: new Uint8Array()}));
+
+test('Input generators "final" runs once with multiple empty iterable input sources, sync', () => {
+	let finalCount = 0;
+	const {stdout} = execaSync('stdin.js', {
+		stdin: [[], [], {
+			* final() {
+				finalCount += 1;
+				yield foobarString;
+			},
+		}],
+	});
+	assert.equal(stdout, foobarString);
+	assert.equal(finalCount, 1);
+});
+
+test('Input generators "final" can produce binary input without an input source, sync', () => {
+	const {stdout} = execaSync('stdin.js', {
+		stdin: {
+			* final() {
+				yield new TextEncoder().encode('first\nsecond');
+			},
+			binary: true,
+		},
+	});
+	assert.equal(stdout, 'first\nsecond');
+});
+
+test('Input generators "final" output passes through the next transform without an input source, sync', () => {
+	const calls = [];
+	const {stdout} = execaSync('stdin.js', {
+		stdin: [
+			{
+				* final() {
+					yield 'first';
+					yield 'second';
+				},
+			},
+			{
+				* transform(line) {
+					calls.push(line);
+					yield line.toUpperCase();
+				},
+				* final() {
+					yield 'last';
+				},
+			},
+		],
+	});
+	assert.equal(stdout, 'FIRST\nSECOND\nlast');
+	assert.deepEqual(calls, ['first', 'second']);
+});
+
+test('Input generators "final" errors are reported without an input source, sync', () => {
+	const cause = new Error('Input final failed');
+	assert.throws(() => {
+		execaSync('stdin.js', {
+			stdin: {final: throwingGenerator(cause)().transform},
+		});
+	}, {cause});
+});
+
+test('Input generators "final" errors respect reject: false without an input source, sync', () => {
+	const cause = new Error('Input final failed');
+	const result = execaSync('stdin.js', {
+		stdin: {final: throwingGenerator(cause)().transform},
+		reject: false,
+	});
+	assert.equal(result.failed, true);
+	assert.equal(result.cause, cause);
+});